The present invention relates to a new and improved method of operating a two-phase gripper loom or weaving machine and to a two-phase gripper loom for the performance of such method.
Generally speaking, the two-phase gripper loom of the present development is of the type comprising two loom units arranged adjacent to one another, wherein each of their heald frames can be actuated in a phase shifted manner by a related one of two heald frame positioning devices. Each heald frame positioning device associated with the related loom unit is provided with heald frame positioning cams and a rotary shaft. Both of these rotary shafts are conjointly driven by the main shaft of the weaving machine or loom.
With such double cloth or two-phase gripper looms the so-called weft thread insertion--also simply weft insertion--occurs alternately, and thus, the periodic shed formation at the one woven fabric web or cloth is performed so as to be offset with respect to the periodic shed formation at the other woven fabric web or cloth by an angle of the crank shaft which, as a rule, amounts to 180.degree.. This means that, following a machine stoppage or shutdown which has been manually triggered or through the agency of a functional supervising or monitoring device, the one loom unit comes to a standstill with its weaving shed closed and the other loom unit with its weaving shed open.
However, with a number of textile materials even a resting period or dwell time of a few minutes with the shed open can lead to such distortions of the warp threads that the fabric produced thereafter only is a reject or, at any rate, a fabric of diminished quality.